Your Privacy Matters

Privacy Policy

Effective date: 1 January 2026
Last updated: 27 May 2026
Tools Master Hub
Plain English Summary: The Sleep Calculator runs entirely in your browser. We don't collect, store, or sell personal health data. Your dark mode preference is saved in your own browser's localStorage — not on our servers. Google AdSense may set cookies for ads. That's it.

Table of Contents

1

Information We Collect

The Sleep Calculator is a client-side web application. We do not operate a database of user data. The following describes what is and is not collected:

What we DO NOT collect:

  • Sleep times, bedtimes, or wake-up times you enter into the calculator
  • Your name, email address, or any personally identifiable information (unless you voluntarily contact us via the Contact page)
  • Health or medical data of any kind
  • Location data beyond your browser's reported timezone (used only to display your local time; never transmitted to us)
  • Microphone, camera, or sensor data

What is stored locally in your browser:

  • Dark mode preference — saved in your browser's localStorage under the key darkMode. This never leaves your device.
  • Music widget state (volume, last sound played) — stored locally in your browser only.

If you contact us via the Contact page, we receive your name, email address, and message for the purpose of replying to you.

2

How We Use Information

Any information received through the voluntary Contact form is used solely to respond to your enquiry. We do not use it for marketing, add it to mailing lists, or share it with third parties.

We do not use your data to build profiles, serve targeted advertising based on your personal information, or make automated decisions about you.

Core principle: No data you enter into the sleep calculator is ever sent to our servers or stored anywhere outside your own browser.
3

Cookies & Local Storage

This website uses browser localStorage (not cookies) to save your UI preferences (dark mode, volume). These are not tracking technologies — they are simple key-value pairs stored only on your device and never transmitted.

Cookies set by this site itself: None.

Cookies set by third parties (see Section 4 for full details):

  • Google AdSense may set cookies to serve and personalise advertisements. These are governed by Google's own privacy policy.
  • Google Fonts is loaded from Google's CDN. Google may log requests to their font servers.

You can clear localStorage and cookies at any time through your browser settings. Clearing localStorage will reset your dark mode preference.

4

Google AdSense & Analytics

This website displays advertisements served by Google AdSense (Publisher ID: ca-pub-8358460291048758). Google AdSense uses cookies to serve ads based on your prior visits to this and other websites.

Google's use of advertising cookies enables it and its partners to serve ads based on your visit to this site and/or other sites on the Internet. You may opt out of personalised advertising by visiting Google Ads Settings.

Important: We have no control over the cookies set by Google AdSense. Their behaviour is governed entirely by Google's Privacy Policy.

We do not currently use Google Analytics or any other analytics platform on this page. If analytics are added in the future, this policy will be updated and users will be notified.

5

Third-Party Services

This page loads resources from the following third-party services:

  • Google Fonts (fonts.googleapis.com) — for typography. Google may log font requests. See Google Fonts Privacy FAQ.
  • Google AdSense — for serving advertisements. See Google's policy above.

All ambient sound generation uses the Web Audio API — a built-in browser capability. No audio is loaded from external servers. All sounds are synthesised entirely within your browser using JavaScript.

We do not use social media tracking pixels, heat-mapping tools, session recording software, or any analytics third party beyond those named above.

6

Data Security

Because the Sleep Calculator does not transmit or store personal data on our servers, the attack surface for a data breach related to this tool is minimal.

Our website is served over HTTPS (TLS encryption) to protect data in transit. Any contact form submissions are transmitted via your email client using your own provider's security.

We encourage you to keep your browser and operating system up to date to maintain the best security posture when using any web application.

7

Children's Privacy

The Sleep Calculator is a general wellness tool suitable for all ages. We do not knowingly collect personal data from children under 13 (or under 16 in the EU/EEA under GDPR).

If you believe a child has submitted personal information to us via the Contact form, please contact us at contact@toolsmasterhub.com and we will delete it promptly.

Note: Google AdSense's personalised advertising is subject to Google's own Children's Online Privacy Protection policies. Parents may wish to use browser extensions to block advertising on devices used by children.
8

Your Rights (GDPR / CCPA)

Depending on your location, you may have the following rights regarding personal data:

  • Right of Access — to know what personal data we hold about you.
  • Right to Rectification — to correct inaccurate personal data.
  • Right to Erasure ("Right to be Forgotten") — to request deletion of your personal data.
  • Right to Object — to object to processing of your data for certain purposes.
  • Right to Data Portability — to receive your data in a structured, machine-readable format.
  • Right to Opt Out (CCPA) — California residents have the right to opt out of the sale of personal information. We do not sell personal information.

Since this tool collects no personal data through its core function, most of these rights apply only to data shared voluntarily via contact messages. To exercise any right, email us at contact@toolsmasterhub.com.

For rights related to Google AdSense data, please contact Google directly via myaccount.google.com.

9

Changes to This Policy

We may update this Privacy Policy from time to time to reflect changes in our practices or legal requirements. When we do, we will update the "Last updated" date at the top of this page.

We encourage you to review this policy periodically. Continued use of the Sleep Calculator after any changes constitutes acceptance of the updated policy.

Material changes (such as introducing new data collection) will be prominently announced on the main calculator page.

10

Contact Us

If you have any questions, concerns, or requests regarding this Privacy Policy or your personal data, please reach out:

We aim to respond to all privacy-related enquiries within 5 working days.

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